Violet goby

Appearance

The Violet goby has a long, slender, eel-like body. Its dorsal and anal fins run almost the entire length of the body. The teeth are very sharp; however these are used for scraping algae off rocks, not fighting. When kept in good condition, dragon gobies develop an attractive, iridescent, silvery-blue metallic color with a gold blotch pattern. Violet gobies seen in pet stores are generally 3 to 5 inches long. In the wild, violet gobies can grow to 24 inches long. However, in captivity they seldom grow past 15 inches . Males tend to have long, pointed genital papilla, while that of the females are shorter, blunt, and yellow in color.

Behavior

Despite its fierce looks, large mouth, and many teeth, the violet goby is a predator scavenger. If well fed, it usually will not bother smaller fish. Any small, peaceful, brackish water-tolerant fish can coexist with violet gobies. Examples include mollies, guppies, swordtails, platies, bumblebee goby, and glass fish. The violet goby is only kept with peaceful fish, as it has poor eyesight and may be bullied by more boisterous fish.
However, if two violet gobies exist in a tank too small, one will eventually claim the entire area their own territory and fiercely defend it.

Habitat

Violet gobies usually inhabit brackish swamps, streams, and estuaries with a muddy substrate. Violet gobies have very small eyes, and as such are primarily scavengers. Their key method of obtaining food is by scooping up mouthfuls of gravel and sorting edible material from the substrate, and then spitting out the substrate and swallowing the food particles. They also use their highly specialized teeth to scrape algae off of rocks.

Reproduction

They typically spawn in a group of one male and three or more females. Females require many hiding places, while the male needs a site to build his nest. Spawning is triggered by feeding on live meaty foods, and a decrease in salinity from 7 parts per thousand to around 5 parts per thousand , followed by an increase to 30 parts per thousand . The male spawns with several females over the course of a day. After spawning, the male guards the eggs. After 1.5–2 days, the eggs hatch. Fry eat infusoria and "green water" for up to a month. They then eat baby brine shrimp nauplii.

Food

Violet gobies usually inhabit brackish swamps, streams, and estuaries with a muddy substrate. Violet gobies have very small eyes, and as such are primarily scavengers. Their key method of obtaining food is by scooping up mouthfuls of gravel and sorting edible material from the substrate, and then spitting out the substrate and swallowing the food particles. They also use their highly specialized teeth to scrape algae off of rocks.Violet gobies are scavengers in the wild and need a varied diet for optimum health, but are limited by two factors, their small throat size and very poor vision. Despite having huge tooth-filled mouths, these fish actually have very small throats and this limits the kinds of foods they eat. They eat both animal and plant-based foods, such as frozen blood worms, frozen tubifex worms, baby brine shrimp, and vegetable flakes. Unless they are in a species specific tank, violet gobies cannot compete with other fish to find food, because of poor eyesight. Violet gobies often feed at night.